(1) Field of the Invention
The present invention relates to technology that cools a sheet on which a toner image is formed.
(2) Description of the Related Art
In image forming apparatus such as printers and copiers, a format is used where toner is transferred to paper (a sheet), and the toner on the paper is fused by the heat of a fixing device and thereafter cooled and caused to solidify so that the toner is fixed to the paper. In such image forming apparatus, after the toner has been fixed to the paper, the paper is discharged into a paper discharge tray while still retaining quite a bit of heat. Thus, sometimes this triggers a phenomenon called “blocking,” where sheets of the discharged paper adhere to each other due to the fused toner.
In order to prevent such blocking, technology is known which uses a fan to take outside air into the conveyance path of the paper and cool the paper by sending the outside air to the conveyance path. A method is also disclosed that the paper is cooled using a cooling roller made of a heat pipe.
Incidentally, in recent years, image forming apparatus have been developed where the processing speed of the image forming process is fast. In such image forming apparatus, it becomes easier for blocking to occur because the paper discharge speed is fast. In the methods described above, there is a limit on the cooling effect; thus, in image forming apparatus where the processing speed is fast, there is the potential for paper that has not been sufficiently cooled to be discharged and for blocking to occur. And in the method described above, the paper is cooled using a cooling roller; thus, there is the potential for adverse effects to occur, such as the offset phenomenon, where some of the toner adheres to the roller and is taken away, and jamming of the paper wrapped around the roller.